Advancements in communication and processing technologies have permitted the development, and implementation, of new types of communication systems. Generally, increased data rates of communication are permitted as a result of such advancements. Increasingly large amounts of data are permitted to be communicated within a selected time period.
New types of communication services, requiring high data throughput rates are possible in such new types of communication systems. Multimedia communication services are exemplary of new types of communication services, permitted now due to such communication-technology advancements. And, many other types of communication services are similarly also possible in communication systems constructed to take advantage of the communication technology advancements.
New-generation cellular, and other radio, communication systems are developed to provide for packet-based communications. Most multimedia communication services are predicated upon packet-based communications. Other communication services are analogously also migrating towards packet-based communications. Different types of communication schemes are used, or proposed for use, in such new communication systems. For instance, at least one WLAN (wireless local area network), to be operable pursuant to a variant of the IEEE (Institute of Electrical and Electronic Engineers) 802.11 specification proposes to utilize OFDM (orthogonal frequency division multiplexing) techniques. OFDM effectively forms a hybrid of a multi-carrier modulation (MCM) and frequency shift keying (FSK) modulation. Frequency-divided carrier frequencies are defined in an OFDM system such as the proposed, WLAN, and the carriers are selected to be orthogonal to one another, such as by separating the carriers by integer multiples of the inverses of symbol durations of parallel bit streams that are to be applied thereto. The orthogonal carriers are transmitted simultaneously, thereby permitting an entire allocated channel to be occupied through an aggregated sum of narrow, orthogonal subbands.
The WLAN, operational pursuant to the variant of the IEEE 802.11 standard. Packet-based communication schemes generally utilize digital communication techniques, and communication stations operable in many packet-based communication systems require the utilization of modems (MOdulators/DEModulators). While operation of modems vary, depending upon the type of communication scheme in which the modems are to be operable, certain characteristics of the modems are important. Characteristics include the cost, size, complexity, programmability, scalability, simplicity, and modifiability of the modem.
Existing modem constructions are sometimes categorized according to their general operational features.
One modem-type category forms a data-flow style modem. Such a modem construction is formed of fixed circuits. The fixed circuits are interconnected by way of fixed connections, and the circuits are driven by a common, centrally-controlled timing circuit. The fixed circuits generally are operable in only one manner, e.g., a circuit is capable of executing only a single algorithm. While acceptable for many implementations, a conventional, data-flow construction is unable readily to be modified, is generally of relatively large physical dimensions, is relatively power-consumptive, and exhibits difficulty of design maintenance. Lack of programmability and scalability are disadvantageous from an economic viewpoint and further adaptability.
Another modem-type category forms a DSP-style modem, i.e., a modem that utilizes a DSP (digital signal processor) in its construction. This type of modem is of improved programmability characteristics relative to a data-flow modem type. That is to say, the details of the modem are contained in software code and data arrangement, all storable in a memory device rather than in a particular interconnection of fixed circuits. However, the specialized nature of the DSP, and hardware structures ancillary thereto, limit the modifiability of the modem constructed therefrom. While more modifiable than a data-flow style modem construction, this modem type also lacks full programmability. A modem of this construction type also cannot therefore be modified easily.
Execution of modem-function algorithms at a processor having a vector architecture would be advantageous as the speed at which the operations can be effectuated would be increased. Fast Fourier Transforming and Viterbi decoding in the demodulator part of the modem would particularly be facilitated.
To date, however, a modem construction type has not been provided that fully takes advantage of the features of a processor having a vector architecture. If a modem utilizing such a processor could be provided modem operation would be facilitated and improved programmability and scalability to the modem would be provided.
A modem construction type utilizing such a vector architecture would be particularly advantageously implemented in a communication system that utilizes OFDM.
It is in light of this background information related to modem operation that the significant improvements of the present invention have evolved.